OSCE Minsk Group co-chairs, Igor Popov (Russia), Jacques Faure (France) and James Warlick (the U.S.), and the Personal Representative of the OSCE Chairperson-in-Office, Ambassador Andrzej Kasprzyk visited the region from May 16 to May 19, a statement posted on OSCE's website said.

The Minsk Group co-chairs visited the region to discuss the process of the peaceful settlement of Armenian-Azerbaijani Nagorno-Karabakh conflict.

They were joined by Ambassador Pierre Andrieu, who will take over as French co-chair in June.

The main objective of their visit was to review the situation in Azerbaijan's Nagorno-Karabakh, Kelbajar, and Lachin regions occupied by Armenia, in accordance with their mandate, the message posted on the organization's website said.

The co-chairs also visited the Sargsang reservoir and discussing its status, they expressed hope that the sides will reach an agreement to jointly manage these water resources to the benefit of the region.

The co-chairs crossed the Azerbaijani-Armenian contact line near the Terter region of Azerbaijan on May 19, the message said.

Moreover, they expressed regret for the continued ceasefire violations and consequent casualties.

In the course of the visit to the region, the co-chairs met with the senior officials in Yerevan and Baku, as well as the de facto authorities of the breakaway Nagorno-Karabakh region. They also met with representatives of the Azerbaijani Community of Nagorno-Karabakh in Baku. In their meetings, the co-chairs discussed elements of the peace process, and stressed that the basis of a lasting settlement remains those elements outlined in statements by the presidents of the co-chair countries from 2009 to 2013.

The conflict between the two South Caucasus countries began in 1988 when Armenia made territorial claims against Azerbaijan. As a result of the ensuing war, in 1992 Armenian armed forces occupied 20 percent of Azerbaijan, including the Nagorno-Karabakh region and seven surrounding districts.

The two countries signed a ceasefire agreement in 1994. The co-chairs of the OSCE Minsk Group, Russia, France and the U.S. are currently holding peace negotiations.

Armenia has not yet implemented the U.N. Security Council's four resolutions on the liberation of the Nagorno-Karabakh and the surrounding regions.